Reaction products of i



Patented Dec. 25, 1945 REACTION PRODUCTS OF 1,4-DICHLORO- 2-BU'IENE Robert F. Taylor, Teri-e Haute, Ind.

No Drawing. Application March 25, 1944, Serial No. 528,174

4 Claims.

My invention relates to new compositions of matter, and more particularly, it relates to 2- butene-1,4-diol dialkyl diphthalates having the following general structural formula:

wherein the substituent R represents an alkyl group.

Compounds of the above type may be synthesized by reacting 1,4-dichloro-2-butene or a suitable halogen analog thereof with an alkali metal alkyl phthalate. The compound may be readily prepared in either one of the two following ways: by reacting the desired alkali metal alkoxide with phthalic anhydride in a known manner, or by reacting the desired aliphatic alcohol with phthalic anhydride, preferably in a ratio of about two moles of alcohol for each mole of phthalic anhydride to yield the corresponding hydrogen alkyl phthalate which may then be converted to the alkali metal alkyl phthalate by reaction with the desired alkali metal hydroxide. In instances where the hydrogen alkyl phthalate is readily purified and the alkali metal alkyl phthalate is easily freed from water, either type of the aforesaid phthalic acid derivatives may be employed. However, when the hydrogen alkyl phthalate cannot be readily purified, or when the alkali metal alkyl phthalate derived from the aforesaid hydrogen alkyl phthalate cannot be readily dried, it is preferable to prepare such alkali metal alkyl phthalates through the alkali metal alkoxide, as indicated above. 'After the alkali metal alkyl phthalate has been prepared, 1,4-dichloro-2-butene is added to a solution consisting of the alkali metal alkyl phthalate dissolved in a suitable solvent, such as an alcohol corresponding to that employed in esterifying the phthalic anhydride, in a ratio of approximately one mole of 1,4-dichloro-2-butene to two moles of phthalic acid derivative. This mixture is then heated under reflux until precipitation of the alkali metal halide appears to be complete. The resulting mixture is then filtered and the filtrate concentrated by heating the same under'reduced pressure. After the solvent has thus been removed, the residue obtained consists of substantially pure 2-butene-1,4-diol dialkyl diphthalate. If the product is normally a solid, it can be recrystallized from a suitable solvent,

alkali metal phthalate' -mately thirty minutes.

such as one of the lower aliphatic alcohols; for example, ethanol.

As examples of esters included by the above generic formula and which are considered as lying within the scope of my invention, there may be mentioned 2-butene-L4-diol diethyl diphthalate. 2-butene-1,4-diol dimethyl diphthalate, Z-butene- 1,4-diol diisopropyl diphthalate, 2-butene-1,4-diol di-2-ethylhexyl diphthalate, 2-butene-l,4-diol dibutyl diphthalate, and the like.

My invention may be further illustrated by the following specific examples.

EXAMPLE I To a refluxing solution consisting of 57.5 g. of metallic sodium and 1 liter of absolute methanol was slowly added 370 g. of phthalic anhydride. Immediately upon the addition of phthalic anhydride, a vigorous reaction occurred and a fiocculent precipitate formed. Thereafter an additional 300 m1. of methanol was added and the suspension was refluxed for a period of approxi- A total of 144 g. of 1,4- dichloro-2-butene was next added and the resultant mixture was then refluxed for twentyfour hours on a steam bath. The precipitate thus formed which consisted of sodium chloride was then filtered off and the filtrate concentrated in vacuo. After part of the methanol had been removed and the temperature decreased to 10 C., a precipitate formed. This solid was filtered off, washed thoroughly with water, and dried. It amounted to 141.6 g. and was found to be substantially pure 2-butene-1,4-dio1 dimethyl diphthalate. Further evaporation of he filtrate gave 180.3 g. of crude ester. The total yield of crude material was 321.9 g., representing 67.9 per cent of theory. This material was sufficiently pure for f the majority of technical uses and could be further purified by recrystallization from methanol.

EXAMPLE II A mixture consisting of 444 g. of phthalic anhydride and an equal amount of butanol was heated for 10 minutes. After all of the phthalic anhydride had dissolved, the solution was then chilled and the precipitated solid filtered ofi and neutralized with a solution of 81.5 g. of sodium hydroxide dissolved in the minimum amount of water. The solution was cooled during neutralization to prevent hydrolysis of the ester. Thereafter, 700 ml. of butanol was added and the water removed as an azeotrope with butano1 until the temperature of the reaction vessel reached C. at which point a solid product began to separate. One hundred and nineteen grams of 1,4-dichloro-2-butene was then added and the mixture stirred and refluxed under a water separater for eighteen hours to remove all of the obtained from sinale preparations of the variom esters listed.

The new esters of my invention have been found useful as plasticizers for numerous filmwater'. The oil layer was then returned from 5 forming compositions as well as various types the separator to the reaction vessel and the mixof synthetic rubber, such as for example, those ture refluxed for an additional six hours. The prepared by the polymerization of vinyl chloride salt formed during the reaction was filtered oi! and certain copolymers thereof. The new esters and the filtrate distilled at atmospheric pressure of my invention are also useful in the synthesis to remove the butanol. The residue was heated 10 of new and valuable oraanic compounds. Other to 250' C. at 5 mm. pressure to remove dlbutyl uses of these materials will be apparent to those phthalate, phthalic' acid and other impurities. skilled in the art. The 2-butene-1,4-diol dibutyl diphthalate thus My invention now having been described. obtainedwas then decolorized with 2 per cent what I claim is: Norite (dec l l nfl carbon) by h ing at 100 16 1. 2-butene-L4-diol dialkyl dlphthalates havfor a period of one hour. The material thus obing the following structural formula: tained was still dark in color and amounted to 0 0 :g'lggarresponcal. ding to a yield of 60.9 per cent 1L Cmclkcncmoig The table appearing below lists various physi- 20 C on [no G cal properties of certain esters of my invention f which were prepared in accordance with the seneral method outlined in t foregoing e wherein the substituent R represents an alkyl amples. group.

Table Saponifloation Percent when Percent Compound Physical state equiv-lent Found Theory Found Theory Found Theory 2-butene-L44iioldimetbyldiphthalate Whitesolid M.P.82C was 103.8 64.16 our 4.01 no B-butene-Lklioldiethyldiphthalate White solid M.P.67O was 110.0 65.35 can an an 3-butene-l,4-dioldiisoprop ldi hthalate.. Oil-decompdsltlonbegan at166C.(5mm.) 118.4 111.0 00.0! new an ms 2-butene-l,4-dioldibutyld n amen".-- on-mblemwcwmm.) use mo 68.14 01.15 an I. a 2-butenel,4-dioldi-2ei.byl ryldiphthalate.--.-.do 15m mo was 1106 s04 zen Although the above physical properties may be helpful in identifying these compounds, I"; 18 to be understod that I do not desire to limit myself to products having the exact physical characteristics described abovesince the data were 2. 2-butene-L4-diol dimethyl diphthalate. 3. 2-butene-1,4-diol diethyl diphthalate. -4. 2-butene-1,4-diol dibutyl diphthalate.

ROBERT F. TAYLOR. 

